The subject invention is an undergravel wet/dry trickle filter system having advantages over known systems. It is mounted inside an aquarium, eliminates the need for hoses and noisy motors that can leak and cause damage, is less expensive to manufacture than conventional wet/dry filter systems, and is considerably quieter than conventional systems.
Undergravel filtration systems are well known in the art. For example, Byrne, et al., U.S. Pat. No. 4,817,561, issued Apr. 4, 1989, describe an aeration and filtering system for use in an aquarium which utilizes a porous filter bed that is spaced above the tank bottom with a pumping means located in a chamber below the filter bed. This filter, as well as other undergravel filters, uses aerobic bacteria in the gravel to destroy wastes and secretions. In contrast, the subject invention does not use gravel as a bacterial bed. This provides the advantage of maintaining the gravel in a pristine condition.
External biological aquarium filters are also known in the prior art. For example, Willinger, U.S. Pat. No. 4,265,751, issued May 5, 1991, describes an external aquarium filter utilizing a filter bed of open cell reticulated foam plastic material, such as polyurethane foam and a layer of activated carbon. Unfortunately, disadvantages of the Willinger system include the need to back flush the filter to remove accumulated sediment. The subject invention, on the other hand, utilizes a sponge to trap particulates, thereby overcoming a problem found in prior art undergravel filters.
The use of oxidation of a means for purifying, sterilizing and clarifying water is known. Bullock, U.S. Pat. No. 4,874,509, issued Oct. 17, 1989, describes such a system for use in a swimming pool. Although such systems have not been typically employed in aquariums, the advantages taught by Bullock have been incorporated into the subject filtration system.
Biological, mechanical and chemical adsorption elements have been described in external aquarium filtration means. Orensten, et al., U.S. Pat. No. 3,957,634, issued May 18, 1976, describe such a filtration system. Although this filtration means and method accomplish similar end results as the subject invention, the Orensten, et al. system costs substantially more than the subject apparatus and is not contained within the aquarium. Hall, U.S. Pat. No. 4,268,387, issued May 19, 1981, describes a highly complicated filtration system utilizing a plurality of levels for conducting filtration. Although this patent discusses biologically clean and chemically clean undergravel systems, the system described is not a flow through system and does not include the benefits of a highly oxidized bed.
A major cause of system breakdown in a conventional wet/dry filter is water evaporation that causes the sump to go dry, stopping circulation and frequently burning out the sump pump motor unless expensive electronic sump control devices are installed. In addition, if the siphon to the filter stops for any reason, water from the sump will continue to be pumped into the tank causing it to overflow onto the floor. On the other hand, if motor failure occurs, the siphon will drain the aquarium and water will overflow from the filter. Because of these problems, taking a vacation requires someone trained in maintaining proper water levels to come daily to your home/office. The only alternative to hiring help was to purchase an expensive system to cap the sump level, requiring installation of water lines from a sink or house plumbing to the aquarium. However, even with such a system, ballcock shut off failure can result in serious flood damage. In contrast, the subject filter system can operate until most of the water in the tank has evaporated.
Accordingly, the subject invention provides a solution to the long felt need for a wet/dry filter system which does not require manned supervision or expensive mechanical water level maintenance. The subject system is self-contained and comprises mechanical, biological, chemical (additives and absorbing), reactive systems that leave water more purified than former systems, while requiring fewer water changes and less maintenance. Further, unlike conventional wet/dry systems, it is unnecessary to prime siphons after changing water, since the filter is contained below the water level, even during water changes.
The subject system, therefore, represents a major breakthrough in aquarium filtration. It is extremely small, powerful, inexpensive to manufacture, requires no knowledge on the part of the user (just put the filter into the tank, cover it with gravel and connect the air pump to the filter), works automatically and requires no costly equipment or metering devices. Moreover, the subject system provides a combined oxygen reactor chamber and bacterial chamber. This novel concept maximizes bacterial bed effectiveness, while saturating the water with oxygen which oxidizes chemicals not acted upon by the aerobic bacteria together with byproducts of bacterial decomposition.